John Isner overcomes Tommy Robredo at China Open

John Isner has reached the quarter-finals of the China Open thanks to a three-set victory over Tommy Robredo.

The eight seed was broken twice in the opening set before Robredo clinched it 6-3, but his serve proved to be more reliable in the second as he responded by winning 7-5.

The American was in trouble at 4-5 in the decider when Robredo brought up a match point, though the Spaniard's failure to convert saw the contest head to a tie-break.

Isner moved into a solid 3-1 lead in the breaker, and he was able to close out the hard-fought encounter 3-6 7-5 7-6(4) to seal a place in the last eight.